Add docs for the supported numeric dtypes

Author: seisman

doc/techref/array_dtypes.md

@@ -0,0 +1,35 @@
+# Supported Array Dtypes
+
+PyGMT uses NumPy arrays to store data and passes them to the GMT C library. In this way,
+PyGMT can support a wide range of dtypes. This page documents array dtypes supported by
+PyGMT.
+
+## Numeric Dtypes
+
+For 1-D and 2-D arrays, PyGMT supports most numeric dtypes provided by NumPy, pandas, and
+PyArrow.
+
+**Signed Integers:**
+
+- `numpy.int8`, `numpy.int16`, `numpy.int32`, `numpy.int64`
+- `pandas.Int8`, `pandas.Int16`, `pandas.Int32`, `pandas.Int64`
+- `pyarrow.int8`, `pyarrow.int16`, `pyarrow.int32`, `pyarrow.int64`
+
+**Unsigned Integers:**
+
+- `numpy.uint8`, `numpy.uint16`, `numpy.uint32`, `numpy.uint64`
+- `pandas.UInt8`, `pandas.UInt16`, `pandas.UInt32`, `pandas.UInt64`
+- `pyarrow.uint8`, `pyarrow.uint16`, `pyarrow.uint32`, `pyarrow.uint64`
+
+**Floating-point numbers:**
+
+- `numpy.float32`, `numpy.float64`
+- `pandas.Float32`, `pandas.Float64`
+- `pyarrow.float32`, `pyarrow.float64`
+
+For 3-D {class}`xarray.DataArray` objects representing raster images, only 8-bit unsigned
+intergers (i.e., `numpy.uint8`) are supported.
+
+## String Dtypes
+
+## Datetime Dtypes

doc/techref/index.md

@@ -8,6 +8,7 @@ visit the {gmt-docs}`GMT Technical Reference <reference.html>`.
 ```{toctree}
 :maxdepth: 1
 
+array_dtypes.md
 projections.md
 fonts.md
 patterns.md